Author Topic: 455 hard starter  (Read 163 times)

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Offline Randy

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455 hard starter
« on: April 05, 2015, 07:09:40 pm »
My friend has a 455 that requires 10 pumps of the primer bulb to start. He says he sometimes has to pull about 25-30 times before it starts. Sometimes it doesn't start and he leaves it set for awhile and then will try again. Usually it will start. I think it gets flooded and he should not pump the primer as much. Any other tips or suggestions?

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Offline 660magnum

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Re: 455 hard starter
« Reply #1 on: April 05, 2015, 07:35:16 pm »
The pump was not intended to pump raw fuel into the engine. The pump merely draws fuel through the carburetor and back to the tank so the carburetor can function normally as intended.

If the 455 floods as a result of working the pump bulb, then there is a problem with the needle and seat of the metering valve (leaking) inside the carburetor.
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Offline Eccentric

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Re: 455 hard starter
« Reply #2 on: April 06, 2015, 07:01:38 pm »
That's it in a nutshell.  This saw has a purge system rather than a primer.  You could pump the purge bulb 100 times and it wouldn't flood the saw so long as the needle/seat were holding.
-Aaron

For older saws:
Tune the H side so that it 4-strokes (burbles) at WOT unloaded and just cleans up when under load.
When you lift cutting load, the saw should immediately revert to 4-stroking.  Fine tune the transition point for the wood you're cutting.

Offline 660magnum

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Re: 455 hard starter
« Reply #3 on: April 06, 2015, 07:09:08 pm »
The carbs have a pump on one side and a demand regulator on the other.

The pump keeps fuel in the metering chamber of the carb and the regulator lets fuel into the carburetor venturi as manifold vacuum increases from the engine turning over faster.

The pump is run by the impulse line.
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That knowledge can live after us... and that "Pays It Forward".
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Offline Randy

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Re: 455 hard starter
« Reply #4 on: April 07, 2015, 05:01:17 pm »
OK, he told me that he needs to pump the "bulb" 10 times before starting. Is that normal or is he not doing something right. This is a refurbished saw if that makes any difference. Any suggestions on how to make it easier to start the saw. Your comments are very informative. Thanks in advance.  Randy

Offline Spike60

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Re: 455 hard starter
« Reply #5 on: April 07, 2015, 06:36:52 pm »
455 is one of the easiest/reliable starting saws I've ever seen. Like has been said, the saw cannot be flooded with the primer bulb.

Question 1: How many times does he pull the rope with the choke on? Over-choking is the most common way to flood a saw. I'm guessing he's missing the initial "pop" and continuing to pull with the choke on. This is pretty common.

Question 2: Was this saw set up and adjusted at time of purchase? Too lean on the lo adjustment makes for a harder starting saw. Another indication here would be real boggy acceleration on start up unti, warm.

Question 3: Does the primer bulb firm up/fill up after 3-4 pumps? If it stays empty the carb is probably junk. But this issue is generally found on a saw that constantly stalls, so if the saw runs OK once started, then don;t worry about this one.
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Offline Randy

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Re: 455 hard starter
« Reply #6 on: April 08, 2015, 11:39:15 am »
Spike, thanks for the suggestions.I will definitely pass those along.

 

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